Sulfur-containing cycloaliphatic compound, filled sulfur-vulcanizable elastomer composition containing sulfur-containing cycloaliphatic compound and articles fabricated therefrom

Abstract

A sulfur-containing cycloaliphatic compound, useful as a crosslinker for filled sulfur-vulcanizable elastomer compositions, is represented by the general formula: G[-CaH2a—S[C(═O)]bR]n wherein G is selected from the group consisting of: saturated, monocyclic aliphatic group of valence n containing from 5 to 12 carbon atoms and optionally containing at least one halogen, and saturated monocyclic silicone [RSiO—]n[R2SiO—]p group of valence n; wherein each R independently is a hydrogen or monovalent hydrocarbon of up to 20 carbon atoms; each occurrence of subscripts a and b independently is an integer wherein a is 2 to 6 and b is 0 or 1; p is an integer of from 0 to 3; and, n is an integer of from 3 to 6, with the provisos that when b is 0, R is a hydrogen atom, and when G is a non-halogenated, saturated monocyclic aliphatic group of 6 carbon atoms, n cannot be 3.

The invention claimed is: 
     
       1. A filled sulfur-vulcanizable elastomer composition which comprises:
 (i) at least one sulfur-vulcanizable elastomer; 
 (ii) at least one particulate filler; and, 
 (iii) a crosslinking effective amount of, as crosslinker for sulfur-vulcanizable elastomer (i), at least one sulfur-containing compound of the general formula (1):
   G[-C a H 2a —S[C(═O)] b R] n   (1)
 
 
 
       wherein:
 G is selected from the group consisting of a saturated, monocyclic aliphatic group of valence n containing from 5 to 12 carbon atoms, optionally containing at least one halogen, and a saturated monocyclic silicone group of valence n; 
 each R is a hydrogen; 
 each occurrence of subscripts a and b is independently an integer wherein a is 2 to 6; b is 0; and, n is an integer of from 3 to 6. 
 
     
     
       2. The filled sulfur-vulcanizable elastomer composition of  claim 1  wherein sulfur-vulcanizable elastomer (i) is at least one member selected from the group consisting of ethylene-propylene copolymer (EP), ethylene-propylene-diene terpolymer (EPDM), cis-1,4-polyisoprene rubber, emulsion polymerization-prepared styrene/butadiene copolymer rubber, organic solution polymerization-prepared styrene/butadiene rubber, 3,4-polyisoprene rubber, isoprene/butadiene rubber, styrene/isoprene/butadiene terpolymer rubber, cis-1,4-polybutadiene rubber, medium vinyl polybutadiene rubber, high vinyl polybutadiene rubber, styrene/isoprene copolymer, emulsion polymerization-prepared styrene/butadiene/acrylonitrile terpolymer rubber, butadiene/acrylonitrile copolymer rubber, emulsion polymerization-derived styrene/butadiene (ESBR) having a styrene content of from 20 to 28 percent bound styrene, and an ESBR having a medium to relatively high bound styrene content of from 30 to 45 percent. 
     
     
       3. The filled sulfur-vulcanizable elastomer composition of  claim 2 , wherein the amount of sulfur-vulcanizable elastomer (i) is from 10 to 99 weight percent of the entire weight of the composition. 
     
     
       4. The filled sulfur-vulcanizable elastomer composition of  claim 3 , wherein the amount of sulfur-vulcanizable elastomer (i) is from 60 to 85 weight percent of the entire weight of the composition. 
     
     
       5. The filled sulfur-vulcanizable elastomer composition of  claim 1  wherein particulate filler (ii) is at least one member selected from the group consisting of inert porous filler for carrying silane and filler that is reactive for silane, the filler being combined with at least one silane possessing functionality that is reactive for sulfur-vulcanizable elastomer (i). 
     
     
       6. The filled sulfur-vulcanizable elastomer composition of  claim 5  wherein particulate filler (ii) is from 0.5 to 90 weight percent of the entire weight of the composition. 
     
     
       7. The filled sulfur-vulcanizable elastomer composition of  claim 6  wherein particulate filler (ii) is from 10 to 50, weight percent of the entire weight of the composition. 
     
     
       8. The filled sulfur-vulcanizable elastomer composition of  claim 5  wherein the inert porous filler is carbon and the filler that is reactive for silane is silica. 
     
     
       9. The filled sulfur-vulcanizable elastomer of  claim 5  wherein the silane is a silylated core polysulfide. 
     
     
       10. The filled sulfur-vulcanizable elastomer of  claim 5  wherein the silane is selected from the group consisting of 3-mercaptopropyltriethoxysilane, bis-(3-triethoxysilylpropyl)tetrasulfide, bis-(3-triethoxysilylpropyl)disulfide and S-thiooctanoic acid 3-triethoxysilylpropyl ester. 
     
     
       11. The filled sulfur-vulcanizable elastomer composition of  claim 1  wherein G in sulfur-containing cycloaliphatic compound (iii) is derived from a cyclopentane, cyclohexane or cycloheptane group. 
     
     
       12. The filled sulfur-vulcanizable elastomer composition of  claim 1  wherein sulfur-containing cycloaliphatic compound (iii) is at least 50 weight percent of the mixture of an isomer in which the —C a H 2a —S(C═O) b R groups are in the equatorial position relative to group G. 
     
     
       13. The filled sulfur-vulcanizable elastomer composition of  claim 1  wherein sulfur-containing cycloaliphatic compound (iii) is at least one member of the group consisting of 2-[4,6-bis-(2-mercapto-ethyl)-2,4,6-trimethyl-[1,3,5,2,4,6]trioxatrisilinan-2-yl]-ethanethiol; 2-[3,4-bis-(2-mercapto-ethyl)-cyclopentyl]-ethanethiol; 2-[3,5,7-tris-(2-mercapto-ethyl)-cyclooctyl]-ethanethiol; 2-[3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol; 2-[3,5,7,9-tetrakis-(2-mercapto-ethyl)-cyclodecyl]-ethanethiol; 2-[3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol; 3-[3,4-bis-(3-mercapto-propyl)-cyclohexyl]-propanethiol; 6-[3,4-bis-(6-mercapto-hexyl)-cyclohexyl]-hexanethiol; and a mixture containing 85 weight percent 2-[cis,cis-3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol and at least 5 weight percent 2-[trans,cis-3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol. 
     
     
       14. The filled sulfur-vulcanizable elastomer composition of  claim 13 , wherein sulfur-containing cycloaliphatic compound (iii) is 2-[3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol. 
     
     
       15. The filled sulfur-vulcanizable elastomer composition of  claim 14 , wherein the sulfur-containing cycloaliphatic compound (iii) is a mixture containing 85 weight percent 2-[cis,cis-3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol and at least 5 weight percent 2-[trans,cis-3,4-bis-(2-mercapto-ethyl)-cyclohexyl]-ethanethiol. 
     
     
       16. The filled sulfur-vulcanizable elastomer composition of  claim 1 , wherein G in sulfur-containing compound (iii) is derived from a saturated monocyclic silicone group of valence n. 
     
     
       17. The filled sulfur-vulcanizable elastomer composition of  claim 1 , wherein sulfur-containing compound (iii) is 2-[4,6-bis-(2-mercapto-ethyl)-2,4,6-trimethyl-[1,3,5,2,4,6]trioxatrisilinan-2-yl]-ethanethiol. 
     
     
       18. The cured composition of  claim 1 . 
     
     
       19. The cured composition of  claim 13 . 
     
     
       20. The cured composition of  claim 18  provided as a weather stripping, hose, belt, seal, gasket or shoe sole. 
     
     
       21. The cured composition of  claim 19  provided as a weather stripping, hose, belt, seal, gasket or shoe sole.